Clipping issue

[maartenbreddels]

This screenshot shows two issues:

• One bqplot, which has positive z-index (will need to be solved in bqplot)
• The thumb-handle is clipped, this is something we could fix in the template.

[mariobuikhuizen]

With #28 the thumb-handle is no longer being clipped by the app bar. Now the thumb-handle overlaps the header of the drawer.

This is a feature of v-slider. If the overlap is not intended, it should be fixed in the notebook.